VICTORIA - Auditor general John Doyle calls the B.C. government's carbon offset program a sham.

But the government and operators of the program are firing back, accusing Doyle of ignoring evidence and lacking the proper expertise to examine the system.

In a report released today, Doyle says the government spent $6 million on projects to offset the effects of air pollution, but the projects would have gone ahead anyway so the offsets were not credible, and as a result the government can't claim it has achieved carbon neutrality.

Environment Minister Terry Lake rejected that finding, insisting the province is the first carbon-neutral government in North America, and its offset system is based on international standards.

The Pacific Carbon Trust -- which manages the offset system -- challenged Doyle's findings, saying the two projects he reviewed had already been audited by two independent auditing firms and passed with flying colours. The Trust says Doyle's office lacked the expertise to pass judgement on the program.

For his part, Doyle says his office was subjected an unprecedented and orchestrated campaign of delay and interference, led by the carbon trust and the interests behind carbon offsets.